Dual action triggering valve device for inflatable equipment

ABSTRACT

A DUAL ACTION TRIGGERING VALVE DEVICE FOR EFFECTING INFLATION OF INFLATABLE EQUIPMENT, SUCH AS LIFE PRESERVERS AND THE LIKE, COMPRISING A VALVE BODY THAT MAY BE ATTACHED TO THE INFLATABLE EQUIPMENT AND INCLUDES A COMPRESSED GAS CARTRIDGE PUNCTURING MECHANISM ARRANGED TO BE TRIGGERED EITHER MANUALLY, OR ALTERNATELY, AUTOMATICALLY UNDER PREDETERMINED AMBIENT PRESSURE CONDITIONS.

United States Patent 1191 Novak 111 3,811,461 14 1 ;May2l,1974

DUAL ACTION TRIGGERING VALVE DEVICE FOR INFLATABLE EQUIPMENT Joseph F. Novak, 609 State St., Calumet City, II]. 60409 Filed: Jan. 12, 1972 ApplrNo; 217,331

Inventor:

US. Cl 137/318, 222/5, 222/81 Int. Cl. F16k 51/00 Field of Search 222/3, 5, 81, 509;

References Cited UNITED STATES PATENTS l/I967 Novak...,. 222/5 3,490,649 1/1970 Sheridan ..222/5 Primary Examiner-Henry T. Klinksiek Attorney, Agent, or Firm-Robert C. Brown, Jr. et al.

[ 57] ABSTRACT A dual action triggering valve device for effecting inflation of inflatable equipment,,such as life preservers and the like, comprising a valve body that may be attached to the inflatable equipment and includes a compressed gas cartridge puncturing mechanism arranged to be triggered either manually, or alternately, automatically under predetermined ambient pressure conditions.

7 Claims, 9 Drawing Figures DUAL ACTION TRIGGERING VALVE DEVICE FOR INFLATABLE EQUIPMENT Reference is also made to my earlier U.S. Pat. No.

2,964,050 that pertains to the general type of device in question.

The triggering valve device of my said U.S. Pat. No. 3,298,571 is in the form of a valve body adapted to be secured to the inflatable equipment, in which the valve body has mounted therein a triggering mechanism which is held at a cocked position by a moisture or water soluable element that disintegrates under predetermined conditions of exposure to moisture or water to release the triggering mechanism to permit activation of the triggering mechanism which will then effect puncture of the attached compressed air or gas cartridge for inflating the piece of equipment involved.

A principal object of the present invention is to provide an infaltion controlling trigger release valve arrangement that eliminates the disintegratable element of my said U.S. Pat. No. 3,298,571, and provides for a triggering action that may be manually initiated or permitted to operate automatically under predetermined ambient pressure conditions relative to normal atmospheric pressure.

Another principal object of the invention is to provide an inflation controlling trigger release valve arrangement for inflatable equipment that automatically operates when the device is exposed to ambient pressure exceeding normal atmospheric pressure to a predetermined amount.

Other important objects of the invention are to provide an inflation controlling trigger release valve arrangement for inflatable equipment that effects immediate withdrawal of the puncturing element from the compressed gas cartridge after the puncture of same, that has a dual operational facility insofar as the triggering action is concerned, including automatic opera- 1 tional facility in the event that manual operation is not available or not possible when needed, and that is economical of manufacture, convenient to install and use, and long lived in operation.

In accordance with the present invention, the triggering valve arrangement comprises a valve body appropriately secured to the piece of inflatable equipment involved. which valve body is arranged for application to same of the usual compressed gas or air cartridge. The valve body is provided with a cartridge puncturing member and a driving ram therefor that, on release from a retracted cocked position, moves from the retracted position to an extended position under substantial spring bias, and in so doing drives the puncturing member into puncturing relation with the cartridge. The puncturing member is in fluid tight sealing relation with the housing, and the driving ram operates in a fluid tight sealed portion of the valve body that is in part effected by a trigger actuator which is sensitive to pressure differentials between that of the ambient air and that within the body portion in which the ram operates. The trigger actuator is arranged to operate a trigger release device either manually, or automatically when ambient pressure conditions reach a predetermined amount or multiple above normal atmospheric pressure, as would occur should the inflation equipment become submerged in water.

Still other objects, uses and advantages will be obvious or become apparent from a consideration of the following detailed description and the application drawings.

In the drawings:

FIG. 1 is a sectional view through one embodiment of the invention as applied to a piece of inflatable equipment, showing the triggering mechanism cocked for use to puncture a cartridge of compressed gas or air for the purpose of inflating the equipment under predetermined conditions, or when desired;

FIG. 2 is a fragmental sectional view taken substantially along line 22 of FIG. 1 and illustrating am important part of the trigger setting mechanism;

FIG. 3 is an exploded sectional view of the trigger actuator and associated structure which encloses the valve driving ram mechanism in a fluid seal tight manner;

FIG. 4 is a diagrammatic perspective view of the principal component of the trigger setting mechanism;

FIG. 5 is a view similar to that of FIG. 1, but showing the triggering valve device after it has been operated to puncture the cartridge for inflating the piece of inflatable equipment involved;

FIG. 6 is a view similar to that of FIG. 2, taken substantially along line 6--6 of FIG. 5;

FIG. 7 is a fragmental perspective view illustrating thelocation and cooperation of the trigger setting element of FIG. 4 and associated parts;

FIG; 8 is a view similar to that of FIG. I but illustrating a modified embodiment of theinvention; and

FIG. 9 is a diagrammatic cross-sectional view substantially along line 9-- 9 of FIG. 8.

However, it is to be distinctly understood that the specific drawing illustrations provided are supplied primarily to comply with the requirements of the Patent Code, and that other embodiments of the invention will be obvious to those skilled in the art, which are intended to be covered by the appended claims.

GENERAL DESCRIPTION Reference numeral 10 of FIGS. 1 and 5 generally indicates the triggering valve device of the present invention applied to a piece of inflatable equipment 11 that may be of any suitable conventional character. The piece of equipment 11 is shown for illustrative purposes only, and may in practice be of any type of equipment that is inflatable in character, and which is to be inflated for normal use purposes. Examples are life preservers, boats, rafts, marking buoys and the like. However, the invention is particularly adapted for use in connection with those types of inflatable equipment that areintended to inflate when ambient pressures exceed by a predetermined amount normal atmospheric pressure (which for purposes of this application is defined as being pressures approximating atmospheric pressure at sea level).

Triggering valve device 10 generally comprises a valve body 12 formed to receive a conventional compressed air gas cartridge 14, and including a cartridge puncturing member 16 and a driving ram 18 therefor that is arranged to move from the cocked retracted position of FIG. 1 to the extended position of FIG. 5 for the purpose of driving the puncturing member 16 into puncturing relation with the gas cartridge 14 for release of compressed gas therefrom for the purpose of inflating the piece of equipment 11.

As described in my said US. Pat. No. 3,298,57 l the driving ram 18 is restrained or held in its cocked position of FIG. 1 by trigger device 20 in the form of lever 22 pivoted to the body by pin 24 and formed with arm 26 shaped to engage the flange 28 of ram 18, and including another elongate arm 30 which is adapted to bear against a trigger setting member or element. In accordance with the present invention, the trigger setting element is in the form of non-dissolving or nondisintegrating member 32 (see FIG. 4) against which the lever arm 30 bears under the biasing action of the spring 34 which drives ram 18.

The trigger lever 22 and trigger setting member 32 are mounted in a stud portion 36 of valve body 12, lever 22 operating in a slot 38 formed in stud portion 36, which slot is in communication with rounded recess 40 of the stud portion 36 in which the member 32 is seated for shifting movement between the positions indicated in FIGS. 2 and 6.

The valve setting member 32 in the form illustrated comprises a disc element 42 of generally rounded peripheral configuration and including an upstanding projection 43 defining a ledge 44 on which lever arm 30 is intended to rest in the cocked position of the device 10. Disc element 42 also includes an integral arm 46 operating in slot 48 formed in the valve body stud portion 36, and which is engaged by a trigger actuator member 50 that is received within shell 52 in which the valve body stud portion is housed.

The trigger actuator member 50 comprises disc element 54 carrying 0 ring seal 56 that is inrfluid tight sealing relation with shell 52. However, the fit of seal 56 with shell 52 is sufficiently loose to permit ready movement of actuator member 50 relative to sleeve 52.

The disc element 54 includes cylindrical extension or flange 58 that is adapted to engage arm 46 of the trigger setting member 32 for the purpose of moving same from the position 2 to the position of FIG. 6 to release the trigger 20.

In accordance with this invention. the puncturing member 16 and the parts associated with the driving ram 18 are arranged so that the space within which the driving ram operates is in fluid seal tight relation relative to the ambient air. For this purpose. the puncturing member 16 carries 0 ring seal 60 that is in fluid tight sealing relation with respect to the valve body 12, and shell 52 is also in fluid tight sealing relation with valve body 12. In the form shown in FIGS. '1 and 5, the valve body 12 is flanged as at 62 and the inflatable wall or sheet 64 of the piece of equipment 11 is seated against same and is clamped thereagainst under the action of nut 66 bearing against clamping ring nut 68. Suitable O ring seal 70 is in sealing relation between nut 66 and ring 68.

Nut 66 is applied to threading 72 of valve body stud portion 36, which threading also threadedly receives the end 74 of sleeve 52 that carries 0 ring seal 76 for sealing engagement with the nut 66.

As already indicated, the O ring seal of the valve actuator member 50 is in sealing relation with sleeve 52.

Sleeve 52 includes a cover 78 that is open as at 80 to y define opening 82 which exposes the trigger actuator member 50 to the ambient air and for finger actuation by one desiring to manually trigger device 10 to inflate equipment 11.

The driving ram 18 itself is basically arranged in accordance with my said US Pat. No. 3,298,571,

ssivsdb n eaw.anstratn flares. TQQEPQEL.

88 is kerfed as at 92 to receive a screw driver or the like for the purpose of threading the rod 84 from the full line position of FIG. 5 to the right of FIG. 5 to retract the ram 18 to the position of FIG. 1 wherein the trigger lever arm 26 may be applied behind the ram flange or shoulder 28. This positioning of the lever 22 raises its arm 30 sufficiently so that setting member 32 may be disposed as shown in FIG. 2 whereby the ledge 44 is received under lever arm 30 (see FIG. 2). The rod 84 may then be threaded to dispose its head 87 in the full line position of FIGS. 1 and 8.

The device 10 is thus set or cocked for operation, and one desiring to inflate the piece of equipment 11 may do so by finger pressing trigger actuator 54 from the position of FIG. 1 inwardly of the shell 52 until its ex-' tension 58 engages arm 46 of the trigger setting member 32. Continued inward movement of the trigger actuator 54 will rotate the trigger setting member 32 in the direction indicated by the arrow (see FIG. 2) to substantially the full line position of FIG. 6, wherein the ledge 44 is moved out from under lever arm 30 and lever arm 30 is free to swing clockwise of FIGS. 1 and 5 under the biasing action of spring 34, whereupon the spring 34 drives ram 18 to the left of FIGS. 1 and 8 to in turn drive puncturing member 16 into puncturing relation with the cartridge 14.

Alternately, the. device 10 is arranged to automatically perform the same function when pressure ambient to the device 10 reaches a predetermined multiple of the pressure within valve body 12, or exceeds a predetermined maximum. This would normally be occasioned when the piece of equipment 11 has become submerged in water to a predetermined depth, and the device has not yet been manually operated. The pressure differentials involved result in the trigger actuator member 50 being pressed to the left of FIG. 1 to actuate trigger setting member 32 in the manner previously described to effect puncture of cartridge 14 and resulting inflation of the equipment 11.

In any event, in accordance with the present invention, once the puncturing member 16 has performed its cartridge puncturing function to define opening 102 in the cartridge, the puncture member under the action of its biasing spring 104 returns to its retracted position, the notch 106 that'is defined by the ram 18 accommodating this motion as ram 18 moves to the full line position of FIG. 5 under the action of its spring 34, and against the head 87 of rod 84. This permits free flow of the compressed air gas from cartridge 14 into the inflation chamber or space 107 defined by the equipment 11, through appropriate passage 108 that is formed in the valve body 12.

In the embodiment'of the invention shown in FIGS. 1 7, the valve body 12 is arranged so that the portion of same to which the cartridge 14 is applied is disposed within the piece of equipment 11.

In the embodiment A of FIGS. 8 and 9, the device is arranged so that valve body 12A and cartridge 14 are applied completely externally of the piece of inflatable equipment 11A. The body 12A is formed with an opening 110 to receive adapter body 1 12 which extends into the inflatable chamber 107A that is defined by the piece of equipment 11A, which in the form shown comprises a pair of distendable sheets 114 and 116 appropriately bonded together about their edges to define sealed off space 107A. Adapter body 112 is secured in place by cap nut 118 suitably received on the end 120 of body 112 and against the valve body 12A.

The adapter body 112 houses a conventional air flow control valve member 122 that is diagrammatically illustrated as being spring biased to the closed position by suitable spring 124 with air or other gas emitting from the cartridge 14 when punctured passing to space 107A through valve body passage 108A, and adapter body passages 124, 126 and 128, with the valve member 122 being opened under the pressure involved similar to the common tire valve.

Other than the shaping of parts indicated in FIGS. 8 and 9, the valve body 12A in general and the triggering device 10A in particular are identical to device 10.

SPECIFIC DESCRIPTION Referring again to the device 10, the valve body 12 may be formed of any suitable metallic or plastic material, as may be sleeve 52, trigger actuator member 50 and cap 78. The stud portion 36 is preferably, though not necessarily, cylindrical in configuratiomwith extension 58 of trigger actuator member 50 being of substantially complementary configuration, as indicated in FIG. 5. As already indicated, the valve body stud portion 36 is formed to define slot 38 in which lever 22 is mounted, as well as the rounded recess 40 in which the trigger setting member 32 is mounted, and the groove 48 in which arm 46 of the member 32 operates. Pin 24 is suitably anchored in suitable openings (not shown) appropriately formed in the valve body 12.

Valve body 12 is formed to define a first chamber or way 130 in which ram 18 operates, and a second chamber or way 132 in which the puncturing member 16 operates. The chamber or way 130 is rounded in transverse cross-sectional configuration and defines dead end 134 against which the head 86 of rod 84 may be seated by appropriate rotation of the rod 84 after the trigger lever 22 has been cocked.

The other end 136 of first chamber or way 130 is internally threaded as at 138 to receive cap 90 that is in turn internally threaded as at 142 to threadedly receive the threaded end 88 of the rod 84.

The ram 18 comprises a body 144 having a forward frusto conical camming surface 146 that diverges to rim portion 148, which in turn merges into frusto conical portion 150 that merges into cylindrical portion 152 that in turn merges into flange portion 28.

The frusto conical portion 150, cylindrical portion 152, and flange 28 define the aforementioned notch 106 that accommodates retraction of the puncturing member 16 under the action of its biasing spring 104.

The puncturing member 16 comprises a cylindrical body 154 that is suitably recessed to receive 0 ring seal 60 which is proportioned as to be in fluid seal tight relation with the wall surface 156 that defines way or chamber 132. Spring 104 is seated between body 154 and disc 158 that is press fitted into the end 160 of the chamber or way 132, and which defines opening 162 for the passage of compressed air or gas therethrough. Body 154 has fixed thereto suitable prong 163 which does the actual puncturing of the cartridge 14.

At the other end 164 of the chamber or way 132, annular shoulder 166 is provided against which body 154 is seated under the action of its spring 104, the body 154 including an extension 167 having a rounded end portion 168 which extends through opening 169 in valve body 12 to serve as a cam follower insofar as puncturing member 16 is concerned. Thus, end portion 168 is proportioned to extend into chamber 130 sufficiently to ride on the frusto conical surfaces 146 and 150 as the ram 18 is moved between the positions of FIGS. 1 and 5 to cambody 154 over the ram rim portion 148 for movement into and out of the cartridge 14 to form the opening 102 in the cartridge.

The valve body 12 is preferablythreaded as at 170 to receive the customary threaded end portion 172 of the cartridge 14, and annular sealing disc 174 may be seated againstdisc 158 for sealing purposes. Seal 174 defines central opening 176 through which gas or air released from cartridge 14 may pass into chamber 132.

Valve passage 108, of course, communicates between chamber or way 132 and the space 107 within the piece of equipment 11, passage 108 being suitably enlarged as at 180 and threaded for receiving auxiliary piping,

where desirable, which may be secured thereto by an appropriate threaded connection (not shown) for other applications of device 10. I

As indicated in FIGS. 1 and 5, the valve body 12 and clamp ring 68 are alternately ridged and recessed as indicated at 190 and 192 to provide a good sealing clamping engagement with the inflatable material 64. Clamp nut 66 is suitably recessed as at 194 to receive 0 ring 70 while shell 52 is suitably recessed as at 196 -to receive 0 ring 76. 0 rings 70 and 76 are proportioned so that when the parts are in their assembled relation shown in FIGS. 1 and 5, the O ring seals provide 'a fluid tight seal about the body stud portion 52 where indicated.

Sleeve 52 at its outer end portion is externally threaded as at 198 to threadedly receive cap 78. Sleeve 52 defines cylindrical internal surface 200 with which 0 ring seal 56 is in sliding fluid tight seal relation, the trigger actuation member 50 and surface 200 being in substantial coaxial or concentric complementary relation to insure a good fluid tight seal between the two. Turning now to the embodiment 10A, the valve body 12A is substantially identical to the valve body 12 except that the portion 210 of same that is attached to the piece of equipment 11A is flat axially of the valve body portion 36. The valve .body 12A is applied to the adapter body 112 so that its passage 108 is lined up with the passage 124 of the adapter body 112. The adapter body 112 at its end 220, in the form shown, threadedly receives a head portion 222 that defines the passage 128, through which the shank 224 of valve member 122 extends. The shank 224 is provided with a head 226 suitably affixed thereto which closes off passage 128 under the action of compression spring 124 applied between head portion 222 and spring seat 224 seated against a shoulder 226 of the valve member 122.

The adapter body 112 at its end 220, in the form shown, also has suitable flat nut 230 secured thereto between which and the inflatable wall 114 is applied suitable annular seal member 232. Adapter body 112 extends through the boss structure 234 of the piece of equipment 11A (that is conventional with many forms of life jackets), with an appropriate sealing ring 236 being applied between the boss structure 234 and valve body 12A (see FIG. 9). The cap nut 118 carried on the adapter body 112 is turned against valve body portion 210 to make a seal tight connection of the adapter body 112 with respect to the piece of equipment 11A. As is conventional, the gas or air in the equipment 11A may be released by depressing valve member through opening 237 (after removal of nut 118) that is formed in adapter body 112. Adapter body 1 12 is flattened at 239 for engagementwith flat surface 241 of body 12A to keep passages 108 and 124 lined up.

In the embodiment A, the clamping ring 68 and clamp nut 66 of the embodiment 10 are not required, and consequently sleeve 52 has its end 74 applied directly against a flattened annular sealing surface 240 that is defined by the valve body 12A. The remainder of the device 10A is identical to device 10, as indicated by corresponding reference numerals.

In one commercial embodiment of the invention, the parts are arranged so that, for automatic operation, when the device has been submerged about three feet below sea level, the trigger actuating member 50 will have acted under the differential pressures involved to release the trigger for puncturing the cartridge 14. The driving spring 34 should have strength adequate to insure positive rupture of the cartridge 14. Spring pressure acting on ram 18 effects the rupturing action desired.

It will therefore be seen that .l have provided a triggering inflation control valve arrangement that has a dual operating nature. The device operates automatically to rupture the cartridge when submerged in water to the predetermined depth relative to sea level pres sure (or any other desired pressure level set as a standard), or in the alternate, an operator can finger actuate trigger actuator member 50 to effect the same result by inserting one or more fingers through the access opening 82 of the cap 78.

The devices 10 and 10A eliminate the uncertainty of a dissolvable member trigger setting device, permitting instead either fully automatic action at a predetermined pressure differential acting on the trigger actuator, or manual actuation as desired.

The fact that the inflatable equipment to which the devices of the invention are applied may be air borne at times has no adverse effect on their operability, since when the ambient air pressures are less than the pressure within the body stud portion, valve actuator member 50 will merely be biased to engagement with the sleeve cap 78.

The foregoing description and the drawings are given merely to explain and illustrate the invention and the invention is not to be limited thereto, except insofar as the appended claims are so limited, since those skilled in the art who have the disclosure before them will be able to make modifications and variations therein without departing from the scope of the invention.

I claim:

1. In a device for releasing gas from a compressed gas cartridge, with the device including a valve body in which are shiftably mounted a ram and a cartridge puncturing member actuated by said ram, means for biasing said puncturing member to a retracted position,

with the body including means for mounting the head of a gas cartridge in alignment with the path of movement of said puncturing member, means for driving said ram in one direction along its pathof movement to move said puncturing member into puncturing relation with a gas cartridge mounted on said body by said mounting means as said ram moves under said driving means from a retracted position to an extended posi- -tion, means for retracting said ram against the action of its said driving means, to its retracted position, and trigger means for releasably locking said ram in its said retracted position,

the improvement wherein: said body is formed to define a stud portion in which said trigger means is mounted, and including: a shell applied about said stud portion and secured to said valve body in fluid seal tight relation thereto, said shell including a trigger actuator movably mounted therein for movement relative to said body, said shell being formed to define an opening exposing a portion of said trigger actuator, and trigger release means interacting between said trigger actuator and said trigger means for releasing said trigger means on movement of said trigger actuator in one direction relative to said body to permit said drive means to drive said puncturing member into puncturing relation with a gas cartridge mounted on said body, and means for maintaining said trigger actuator in fluid sealed relation to said shell in all positions of same relative to said shell, said puncturing member being in fluid sealed relation with respect to said body and said ram operating in a .fluid tight sealed portion of said body, which body portion seal is in part defined by said shell and said trigger actuator, whereby said trigger actuator is self actuating to release said trigger means on application of predetermine'd ambient pressures thereon in excess of atmospheric pressure, or alternately, may be manually depressed to release said trigger means. 2. In a device for releasing gas from a compressed gas cartridge, with the device including a valve body in which are reciprocably mounted a ram and a cartridge puncturing member moving in rectilinearpaths disposed substantially at right angles to each other, with the path of movement of said member intersecting that of said ram, means for biasing said member to a retracted position in which a portion of same projects into the path of movement of said ram, with the body including means for mounting the head of a gas cartridge in alignment with the path of movement of said puncturing member, means for driving said ram in one direction along its path of movement and into engagement with said portion of said puncturing member to cam said puncturing member into puncturing relation with a gas cartridge mounted on said body by said mounting means as said ram moves under said driving means to an extended position, means for retracting said ram against the action of its said driving means in the direction opposite its driving direction to a retracted position spaced from said member portion, and trigger means for releasably locking said ram in its said retracted position,

' the improvement wherein:

said body is formed to define a stud portion in which said trigger means is mounted,

and including:

a shell applied about said stud portion and secured to said valve body in fluid seal tight relation thereto,

said shell including a trigger actuator reciprocably mounted therein,

said shell being formed to define an opening exposing a portion of said trigger actuator,

trigger release means interacting between said trigger actuator and said trigger means for releasing said trigger means on movement of said trigger actuator in one direction relative to said body to permit said drive means to cam said puncturing member into puncturing relation with a gas cartridge mounted on said body,

and means for making said trigger actuator in movement accommodating fluid sealed relation to said shell,

said puncturing member being in fluid sealed relation with respect to said body and said ram operating in a fluid tight sealed portion of said body, which body portion seal is in part defined by said shell and said trigger actuator,

whereby said trigger actuator is self actuating to release said trigger means on application of predetermined ambient pressures thereon, or alternately, may be manually depressed to release said trigger means.

3. The improvement set forth in claim 2 wherein:

said trigger actuator comprises a disc element extending transversely of said shell, 1

said means for making said trigger actuator in movement accommodating sealed relation to said shell comprising an O ring seal received about the periphery of said disc element and in sliding relation to said shell.

4. The improvement set forth in claim 2 wherein:

said trigger means includes an arm extending substantially longitudinally of said stud portion,

said trigger release means comprising:

a trigger holding element shiftably mounted in said stud portion and defining a ledge adapted to be engaged by said trigger means arm to position said trigger means to releasably lock said ram in its said retracted position,

said holding element including an arm positioned to be engaged by said trigger actuator,

said holding element being mounted to shift said ledge thereof out of engagement with said trigger means arm under movement imposed on said holding element arm by said trigger actuator to release said trigger means.

5. The improvement set forth in claim 2 wherein:

said ram includes a camming head portion for engaging said puncturing member portion, and a notched portion in which said puncturing head portion seats under said biasing means when said ram is in its extended position to withdraw said puncturing member from the cartridge. 6. The improvement set forth in claim 4 wherein: said stud portion is generally cylindrical in configuration, said trigger actuator comprising:

a disc element extending transversely of said shell and over the outer end of said stud portion,

and a cylindrical wall overlying said stud portion,

said holding element arm being positioned to be engaged by said trigger actuator wall.

7. The improvement set forth in claim 6 wherein:

said shell is formed to limit movement of said'trigger actuator outwardly thereof that may be occasioned when ambient air pressures are less than atmospheric pressure. 

